ANP 1105 Lecture Notes - Lecture 4: Cardiac Muscle, Lactate Threshold, Immunoglobulin Light Chain
31 Jan 2018
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Document Summary
Neural input can increase or decrease heart rate. Cardiac muscle has a different action potential. Long, cylindrical cell with many oval nuclei. Cell membrane is called the sarcolemma, the plasma membrane of the muscle cells. Huge cells (cms in length) which is why multiple nuclei are needed. Sarcoplasm: contains high levels of glycogen & myoglobin & also contains myofibrils, sarcoplasmic reticulum & t-tubules. T-tubules: carry action potential by flowing down sarcolemma membrane, will bring it from cell surface to deep inside the cell increases the muscle fibers surface area. Each muscle fiber (cell) consists of parallel myofibrils. 80% of cellular volume (packed super tight) Contains sarcomeres, which are formed by myofilaments arranged in a pattern. Sarcomeres: extended from one z disc (in between 2 discs) to the next z disc and gives the muscle the name striated muscle. Extend across the i band (light) and partly into the a band (dark)
